1. Field of the Invention
This invention relates generally to an FM receiver, and more particularly is directed to an FM receiver provided with an arrangement by which the multi-path reception of a selected FM broadcast signal can be detected.
2. Description of the Prior Art
When the antenna of an FM receiver receives both radio waves arriving directly from the transmitting antenna and reflected waves which are deflected by mountains, buildings and the like, the received FM broadcast signal is subjected to amplitude and phase modulation due to the fact that the reflected waves or signals are shifted in time relative to the directly received waves or signals. Although the amplitude-modulated components of the received FM broadcast signal can be reduced by the limiter usually contained in the IF amplifier of the FM receiver, the phase-modulated components cannot be thus removed.
In order to avoid the foregoing problem, it has been proposed in the prior art to provide an FM receiver with an oscilloscope by which the user can observe the presence of a characteristic waveform on the oscilloscope when the selected FM broadcast signal contains amplitude-modulated components as a result of the so-called multi-path reception of the FM broadcast signal, whereupon the user can adjust the position of the receiving antenna until such characteristic waveform is removed from the oscilloscope. However, since an oscilloscope is relatively expensive and is not susceptible to inclusion in a desirably compact FM receiver, the foregoing proposal for detecting multi-path reception is not desirable.